1. Field of the Present Invention
The present invention relates generally to the field of analyzing radiated emissions, and, in particular, to the art of more efficiently detecting, measuring, storing and analyzing large volumes of electromagnetic interference data in a wide range or commercial, industrial and other sites and facilities.
2. Background Art
Electromagnetic interference (EMI) has become a major problem today in commercial and industrial environments due to the changing magnitude and frequencies of electromagnetic emissions of electronic equipment such as cellular and portable telephones, hand-held walkie-talkies, radio and television broadcast equipment, and new commercial and industrial specific equipment, most if not all of which generate electromagnetic fields. Because of the wide range of operating characteristics of these devices and the widespread use of such equipment, it is extremely difficult for engineers to determine which of the devices may pose the greatest threat to the electromagnetic environment and which industries are most impacted. All commercial and industrial users of electronic equipment that may radiate electromagnetic emissions have the desire to measure EMI levels within their facilities.
For example, one industry that is potentially impacted by such equipment, as well as by modern electronic healthcare equipment, is the healthcare industry, wherein healthcare facilities are constantly installing new types of end-use electronic equipment in order to improve patient care and reduce operating cost. The continual introduction of new and sophisticated biomedical, diagnostic, and therapeutic devices into the healthcare environment increases the background level of electromagnetic energy in healthcare facilities, and may, in some conditions, jeopardize the very medical procedures that these devices were intended to facilitate. The installation of new equipment may render the environment incompatible with sensitive electronic medical equipment such as electrocardiographs (ECGs), electromyographs (EMGs), electroencephalographs (EEGs), and pacemaker programmers posing a threat to what were once safe electromagnetic environments.
Daily changing conditions at these various commercial and industrial facilities decrease the probability of such facilities being able to determine EMI sources. Such conditions may include the frequency of use of a disturbance-generating piece of equipment, the proximity of an EMI source to a susceptible piece of equipment, or the presence of a disturbance-generating piece of equipment on the same circuit used to power a piece of equipment that is susceptible to emissions.
Due to the prevalence of EMI today in a wide variety of commercial and industrial facilities whose operations depend upon the optimal performance of their equipment, it is extremely important for these facilities to be able to measure and document existing background radiated emissions levels, identify characteristics and location of interference sources, determine the strategic locations for sensitive electronic medical equipment, ensure safe electromagnetic environments, and rank the end-use equipment generating radiated emissions. Having the capability to perform such electromagnetic measurements and analysis allows these facilities to more effectively and strategically position and arrange their particularly EMI sensitive equipment to reduce the probability of an equipment malfunction caused by EMI.
The traditional method for solving electromagnetic emissions problems at a particular site is to measure the magnitude and frequency of the electromagnetic fields in the environment at the site using a basic spectrum analyzer, one or more antenna, attenuator pads, and peripheral data printing and storage devices, all of which can be quite expensive. Using the traditional method, a technically skilled EMI investigator is required to program the spectrum analyzer, to make the desired electromagnetic measurements and to analyze the resulting saved data since the spectrum analyzer is difficult to program and operate. The EMI investigator manually programs the analyzer to collect data such as date, time, and period of measurement with minimum, maximum (peak), and average field strengths within the frequency bands of interests. Unfortunately, the investigator cannot create a test plan that can be carried out automatically without the presence of the investigator at the site and without personal interaction with an analyzer.
Because spectrum analyzers are not generally designed to automatically change scanning parameters over a specific time period, the investigator must monitor the equipment at the site throughout the process to continually reset the parameters of the equipment, capture the data, and manage the data during the characterization process. Critical emissions data may be missed due to the manual reconfiguring of the spectrum analyzer. In many cases, not enough data is collected at the site to determine the few clues and facts necessary to assess the source of an EMI problem, the path of the emissions, and viable options to solve the problem. In other cases, the wrong type of data may be collected (e.g. average values instead of maximum values) during the investigation. Frequently, additional visits to the site are required to capture more data or to change measurement parameters on an analyzer. Thus, the traditional method for collecting electromagnetic emissions data is very cumbersome for the investigator.
Moreover, if the investigator does not use analyzers on a regular basis, the investigator can spend a significant amount of time trying to set up the equipment, and very little time performing the measurements, analyzing the data, and focusing on the source of the EMI problem. This problem is exacerbated when an investigation requires data to be gathered and analyzed in multiple locations at a facility. Due to the complexity of this manual process, the time that it takes to perform an electromagnetic investigation may range from a few days to several weeks depending upon the nature of the EMI source, the type and size of the facility, the type and number of end-use devices experiencing EMI problems, and the purpose of the investigation. These timeframes are disadvantageous or unacceptable for many facilities.
Thus, a need exists for an apparatus that will automatically detect and analyze electromagnetic levels with minimal intervention from an EMI investigator. Moreover, a need exists for an apparatus that is portable, user-friendly, low cost, and capable of being programmed off-site in order to prevent the interruption of the services provided at the site, whether commercial or industrial, while at the same time minimizing the cost of taking EMI measurements.